Fin-Like Field Effect Transistor Patterning Methods for Achieving Fin Width Uniformity

ABSTRACT

FinFET patterning methods are disclosed for achieving fin width uniformity. An exemplary method includes forming a mandrel layer over a substrate. A first cut removes a portion of the mandrel layer, leaving a mandrel feature disposed directly adjacent to a dummy mandrel feature. The substrate is etched using the mandrel feature and the dummy mandrel feature as an etch mask, forming a dummy fin feature and an active fin feature separated by a first spacing along a first direction. A second cut removes a portion of the dummy fin feature and a portion of the active fin feature, forming dummy fins separated by a second spacing and active fins separated by the second spacing. The second spacing is along a second direction substantially perpendicular to the first direction. A third cut removes the dummy fins, forming fin openings, which are filled with a dielectric material to form dielectric fins.

This is a non-provisional application of and claims benefit of U.S.Provisional Patent Application Ser. No. 62/698,536, filed Jul. 16, 2018,the entire disclosure of which is incorporated herein by reference.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experiencedexponential growth. Technological advances in IC materials and designhave produced generations of ICs, where each generation has smaller andmore complex circuits than the previous generation. In the course of ICevolution, functional density (i.e., the number of interconnecteddevices per chip area) has generally increased while geometry size(i.e., the smallest component (or line) that can be created using afabrication process) has decreased. This scaling down process generallyprovides benefits by increasing production efficiency and loweringassociated costs.

Such scaling down has also increased the complexity of processing andmanufacturing ICs and, for these advances to be realized, similardevelopments in IC processing and manufacturing are needed. For example,as fin-like field effect transistor (FinFET) technologies progresstowards smaller feature sizes (such as 32 nanometers, 28 nanometers, 20nanometers, and below), FinFET patterning processes are significantlyconstrained by decreasing process margins. Accordingly, althoughexisting fin patterning processes have been generally adequate for theirintended purposes, they have not been entirely satisfactory in allrespects

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 is a flow chart of a method for fabricating a fin-like fieldeffect transistor (FinFET) device according to various aspects of thepresent disclosure.

FIGS. 2A-2P are fragmentary diagrammatic views of a FinFET device, inportion or entirety, at various fabrication stages, such as thoseassociated with the method of FIG. 1, according to various aspects ofthe present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact.

In addition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.Moreover, the formation of a feature on, connected to, and/or coupled toanother feature in the present disclosure that follows may includeembodiments in which the features are formed in direct contact, and mayalso include embodiments in which additional features may be formedinterposing the features, such that the features may not be in directcontact. In addition, spatially relative terms, for example, “lower,”“upper,” “horizontal,” “vertical,” “above,” “over,” “below,” “beneath,”“up,” “down,” “top,” “bottom,” etc. as well as derivatives thereof(e.g., “horizontally,” “downwardly,” “upwardly,” etc.) are used for easeof the present disclosure of one features relationship to anotherfeature. The spatially relative terms are intended to cover differentorientations of the device including the features.

FIG. 1 is a flow chart of a method 100 for fabricating an integratedcircuit (IC) device according to various aspects of the presentdisclosure. In some implementations, the IC device includes a fin-likefield effect transistor (FinFET) device, which generally refers to anyfin-based transistor device, such as a fin-based, multi-gate transistor.At block 110, method 100 includes forming a mandrel layer over asubstrate. At block 120, a first cut is performed to remove a portion ofthe mandrel layer, thereby leaving a mandrel feature and a dummy mandrelfeature disposed over the substrate. The dummy mandrel feature isdisposed directly adjacent to the mandrel feature. At block 130, method100 proceeds with etching the substrate using the mandrel feature andthe dummy mandrel feature as an etch mask, thereby forming a dummy finfeature and an active fin feature. The dummy fin feature is separatedfrom the active fin feature by a first spacing along a first direction.At block 140, a second cut is performed to remove a portion of the dummyfin feature and a portion of the active fin feature, thereby formingdummy fins separated by a second spacing and active fins separated bythe second spacing. The second spacing is along a second direction thatis substantially perpendicular to the first direction. At block 150, athird cut is performed to remove the dummy fins, thereby forming finopenings. At block 160, the fin openings are filled with a dielectricmaterial, thereby forming dielectric fins. In some implementations,method 100 may continue to fabricate other features of the IC device.Additional steps can be provided before, during, and after method 100,and some of the steps described can be moved, replaced, or eliminatedfor additional embodiments of method 100. The discussion that followsillustrates FinFET devices that can be fabricated according to variousembodiments of method 100.

FIGS. 2A-2P are fragmentary diagrammatic views of a FinFET device 200,in portion or entirety, at various fabrication stages (such as thoseassociated with method 100) according to various aspects of the presentdisclosure. FinFET device 200 may be included in a microprocessor, amemory, and/or other IC device. In some implementations, FinFET device200 may be a portion of an IC chip, a system on chip (SoC), or portionthereof, that includes various passive and active microelectronicdevices such as resistors, capacitors, inductors, diodes, metal-oxidesemiconductor field effect transistors (MOSFETs), complementarymetal-oxide semiconductor (CMOS) transistors, bipolar junctiontransistors (BJTs), laterally diffused MOS (LDMOS) transistors, highvoltage transistors, high frequency transistors, other suitablecomponents, or combinations thereof. FIGS. 2A-2P have been simplifiedfor the sake of clarity to better understand the inventive concepts ofthe present disclosure. Additional features can be added in FinFETdevice 200, and some of the features described below can be replaced,modified, or eliminated in other embodiments of FinFET device 200.

In FIGS. 2A-2D, a fin cut first process is performed to define activeregions of FinFET device 200. The fin cut first process implements amultiple patterning process, such as a double patterning lithography(DPL) process (for example, a lithography-etch-lithography-etch (LELE)process, a self-aligned double patterning (SADP) process, aspacer-is-dielectric patterning (SIDP) process, other double patterningprocess, or combinations thereof), a triple patterning process (forexample, a lithography-etch-lithography-etch-lithography-etch (LELELE)process, a self-aligned triple patterning (SATP) process, other triplepatterning process, or combinations thereof), other multiple patterningprocess (for example, self-aligned quadruple patterning (SAQP) process),or combinations thereof. Generally, multiple patterning processescombine lithography processes and self-aligned processes, allowingpatterns to be created that have, for example, pitches smaller than whatis otherwise obtainable using a single, direct lithography process. Forexample, in some implementations, a patterned sacrificial layer isformed over a substrate using a lithography process, and spacers areformed alongside the patterned sacrificial layer using, for example, aself-aligned process. Then, the patterned sacrificial layer is removed,and the spacers can be used to pattern an underlying layer. In someimplementations, directed self-assembly (DSA) techniques are implementedduring the multiple patterning processes. The present disclosurecontemplates variations to the fin cut first process described below andnotes that various steps may be omitted for ease of discussion.

Turning to FIG. 2A, FinFET device 200 includes a substrate (wafer) 205.In the depicted embodiment, substrate 205 is a bulk substrate thatincludes silicon. Alternatively, in some implementations, substrate 205includes a bulk substrate (including, for example, silicon) and one ormore material layers disposed over the bulk substrate. For example, theone or more material layers can include a semiconductor layer stackhaving various semiconductor layers (such as a heterostructure) disposedover the bulk substrate, where the semiconductor layer stack issubsequently patterned to form fins. The semiconductor layers caninclude any suitable semiconductor materials, such as silicon,germanium, silicon germanium, other suitable semiconductor materials, orcombinations thereof. The semiconductor layers can include same ordifferent materials, etching rates, constituent atomic percentages,constituent weight percentages, thicknesses, and/or configurationsdepending on design requirements of FinFET device 200. In someimplementations, the semiconductor layer stack includes alternatingsemiconductor layers, such as semiconductor layers composed of a firstmaterial and semiconductor layers composed of a second material. Forexample, the semiconductor layer stack alternates silicon layers andsilicon germanium layers (for example, Si/SiGe/Si from bottom to top).In some implementations, the semiconductor layer stack includessemiconductor layers of the same material but with alternatingconstituent atomic percentages, such as semiconductor layers having aconstituent of a first atomic percent and semiconductor layers havingthe constituent of a second atomic percent. For example, thesemiconductor layer stack includes silicon germanium layers havingalternating silicon and/or germanium atomic percentages (for example,Si_(a)Ge_(b)/Si_(c)Ge_(d)/Si_(a)Ge_(b) from bottom to top, where a, care different atomic percentages of silicon and b, d are differentatomic percentages of germanium). Alternatively or additionally, thebulk substrate and/or the one or more material layers include anotherelementary semiconductor, such as germanium; a compound semiconductor,such as silicon carbide, silicon phosphide, gallium arsenide, galliumphosphide, indium phosphide, indium arsenide, indium antimonide, zincoxide, zinc selenide, zinc sulfide, zinc telluride, cadmium selenide,cadnium sulfide, and/or cadmium telluride; an alloy semiconductor, suchas SiGe, SiPC, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and/or GaInAsP;other group III-V materials; other group II-V materials; or combinationsthereof. Alternatively, substrate 205 is a semiconductor-on-insulatorsubstrate, such as a silicon-on-insulator (SOI) substrate, a silicongermanium-on-insulator (SGOI) substrate, or a germanium-on-insulator(GOI) substrate. Semiconductor-on-insulator substrates can be fabricatedusing separation by implantation of oxygen (SIMOX), wafer bonding,and/or other suitable methods.

A patterning layer 210 is disposed over substrate 205. Patterning layer210 includes a material that is different than a material of substrate205 to achieve etching selectivity during a fin etching process, suchthat substrate 205 can be selectively etched with minimal (or no)etching of patterning layer 210, and vice versa. In the depictedembodiment, patterning layer 210 includes a pad layer 212 and a masklayer 214, where pad layer 212 is disposed on substrate 205 and masklayer 214 is disposed on pad layer 212. In some implementations, padlayer 212 includes silicon and oxygen (for example, silicon oxide), andmask layer 214 includes silicon and nitrogen (for example, siliconnitride or silicon oxynitride). In some implementations, pad layer 212is a silicon oxide layer formed by thermal oxidation and/or othersuitable process, and mask layer 214 is a silicon nitride layer formedby chemical vapor deposition (CVD), low pressure CVD (LPCVD), plasmaenhanced CVD (PECVD), thermal nitridation (for example, of silicon),other suitable process, or combinations thereof. In someimplementations, pad layer 212 includes a material that promotesadhesion between substrate 205 and mask layer 214 and/or functions as anetch stop layer when etching mask layer 214. Other materials for and/ormethods for forming pad layer 212 and/or mask layer 214, along withother configurations of patterning layer 210, are contemplated by thepresent disclosure.

Turning to FIG. 2B, a mandrel layer 220 is formed over patterning layer210. Mandrel layer 220 includes an array of mandrels disposed onpatterning layer 220, where adjacent mandrels are separated by spacingS. In the depicted embodiment, mandrel layer 220 includes mandrels 222A,which correspond with active fins to be formed in a portion of substrate205, and dummy mandrels 222B, which correspond with extra mandrelfeatures that are included within mandrel layer 220 to maintain mandrelfeature density (and thus minimize patterning effects, such as fin etchloading effects, that can affect uniformity) and/or correspond withdielectric fins to be formed in a portion of substrate 205, where thedielectric fins are electrically non-functional features of FinFETdevice 200. In some implementations, widths of mandrels 222A aresubstantially equal to desired widths (also referred to as criticaldimensions (CDs)) of fins of FinFET device 200. In some implementations,widths of mandrels 222A are greater than the desired widths of fins ofFinFET device 200 to compensate for consumption of the fins and/orpatterning layers used to form the fins during subsequent processing(for example, to compensate for etch loading effects). Mandrel layer 220includes a material that is different than patterning layer 210 (inparticular, mask layer 214) to achieve etching selectivity during anetching process, such that patterning layer 210 can be selectivelyetched with minimal (or no) etching of mandrel layer 220, and viceversa. Mandrel layer 220 includes a semiconductor material and/or adielectric material that achieves desired etching selectivity, such assilicon, amorphous silicon, silicon oxide, silicon nitride, siliconoxynitride, silicon carbide, other suitable material, or combinationsthereof.

In the depicted embodiment, mandrel layer 220 is formed using a spacerpatterning technique. For example, forming mandrel layer 220 includesforming a patterned sacrificial layer (which includes sacrificialfeatures having a first spacing) over patterning layer 210 using alithography process, forming a spacer layer over the patternedsacrificial layer, etching the spacer layer to form spacers alongsidewalls of each sacrificial feature (for example, the spacer layer isremoved from a top surface of the sacrificial features and a portion ofa top surface of patterning layer 210), and removing the patternedsacrificial layer, leaving spacers having a second spacing (which can bereferred to as a patterned spacer layer, which includes openings thatexpose a portion of patterning layer 210). Mandrel layer 220 andmandrels 222A, 222B can thus respectively be referred to as a spacerlayer and spacers. In some implementations, the spacer layer isconformally formed over the patterned sacrificial layer, such that thespacer layer has a substantially uniform thickness. In someimplementations, the spacers are trimmed before or after removing thepatterned sacrificial layer. Alternatively, in some implementations,mandrel layer 220 is formed by forming a mandrel material layer(including, for example, a dielectric material), forming a patternedresist layer over the mandrel material layer using a lithographyprocess, etching the mandrel material layer using the patterned resistlayer as an etch mask, and removing the patterned resist layer (forexample, by a resist stripping process), leaving a patterned mandrelmaterial layer that includes openings that expose patterning layer 110.Alternatively, in some implementations, mandrel layer 220 is a patternedresist layer, such that mandrel layer 220 includes a resist material.The lithography processes can include forming a resist layer (forexample, by spin-on coating), performing a pre-exposure baking process,performing an exposure process using a mask, performing a post-exposurebaking process, and performing a developing process. During the exposureprocess, the resist layer is exposed to radiation energy (such asultraviolet (UV) light, deep UV (DUV) light, or extreme UV (EUV) light),where the mask blocks, transmits, and/or reflects radiation to theresist layer depending on a mask pattern of the mask and/or mask type(for example, binary mask, phase shift mask, or EUV mask), such that animage is projected onto the resist layer that corresponds with the maskpattern. Since the resist layer is sensitive to radiation energy,exposed portions of the resist layer chemically change, and exposed (ornon-exposed) portions of the resist layer are dissolved during thedeveloping process depending on characteristics of the resist layer andcharacteristics of a developing solution used in the developing process.After development, the patterned resist layer includes a resist patternthat corresponds with the mask. The patterned resist layer can then beused as an etch mask during an etching process to remove portions of anunderlying layer, such as a sacrificial layer or a mandrel materiallayer. The etching process can include a dry etching process (forexample, a reactive ion etching (RIE) process), a wet etching process,other suitable etching process, or combinations thereof. After theetching process, the patterned resist layer can be removed.Alternatively, the exposure process can implement maskless lithography,electron-beam writing, ion-beam writing and/or nanoprint technology.

Turning to FIG. 2C, dummy mandrels 222B of mandrel layer 220 are removedto define fin active regions of FinFET device 200, such as a fin activeregion 224 and a fin active region 226, thereby forming patternedmandrel layer 220′. In the depicted embodiment, fin active region 224 isdirectly adjacent to fin active region 226, such that no other finactive region is disposed between fin active region 224 and fin activeregion 226. Typically, the fin cut first process would continue byremoving all dummy mandrels 222B, such that only mandrels 222Acorresponding with active fins to be formed in substrate 205 remain.However, it has been observed that density variations arising from suchfin cut first techniques can result in etching effects that induce finwidth (or fin CD) differences in active fins that can negatively affectFinFET device performance. For example, when dummy mandrels 222B arecompletely removed from mandrel layer 220, a spacing S2 is definedbetween mandrels 222A in directly adjacent fin active regions, whichresults in areas surrounding each mandrel 222A having differentdensities. The different densities can result in fin active region 224and fin active region 226 having an isolated (iso) mandrel and a densemandrel, where left/right spacing of the iso mandrel is greater thanleft/right spacing of the dense mandrel. Left/right spacing (loading)generally refers to a sum of a spacing between a left sidewall of amandrel and a closest device feature (for example, another mandrel or anedge of substrate 205) along a width direction (here, the x-direction)of the mandrel and a spacing between a right sidewall of the mandrel anda closest device feature along the width direction. In other words, L/Rloading=L spacing+R spacing. In some implementations, a thresholdleft/right loading is defined for classifying a mandrel as an isomandrel or a dense mandrel. For purposes of the present example, it isassumed that the left/right loading corresponding with outermostmandrels 222A is less than the threshold left/right loading, such thatthe outermost mandrels 222A are classified as dense mandrels andinnermost mandrels 222A are classified as iso mandrels (FIG. 2C).

Since left/right loading of mandrels 222A is subsequently transferred toactive fins (when mandrels 222A are used as an etch mask to form theactive fins), an area of substrate 205 that corresponds with isomandrels may etch differently (for example, more quickly or more slowlyin one or more directions depending on whether the etching is configuredanisotropically or isotropically) than an area of substrate 205 thatcorresponds with dense mandrels, such that widths of active finscorresponding with iso mandrels are different than widths of active finscorresponding with dense mandrels. Such etching differences resultingfrom left/right loading are often referred to as fin etch iso/denseloading. In some implementations, it has been observed that an area ofsubstrate 205 that corresponds with iso mandrels etches more slowly thanan area of substrate 205 that corresponds with dense mandrels, such thatwidths of active fins corresponding with iso mandrels (referred to asiso fins) are greater than widths of active fins corresponding withdense mandrels (referred to as dense fins). Such fin etch iso/denseloading has led to less control of short channel effects in iso finscompared to dense fins (for example, increases in drain induced barrierlowering (DIBL)), degrading FinFET device performance and/or resultingin undesired variations in FinFET device performance. Further, as ICtechnology nodes continue to decrease, these issues are exacerbated byever-shrinking gate lengths in FinFET devices fabricated at the advancedIC technology nodes.

The present disclosure proposes inserting dummy fins adjacent toisolated active fins, such as edge fins of a FinFET device, to reduceleft/right loading of isolated active fins. Density in an area ofisolated active fins is thus closer (and, in some implementations,equivalent) to density in an area of dense active fins, thereby reducingfin etch iso/dense loading and improving fin width uniformity. Forexample, in FIG. 2C, the fin cut first process removes a subset of dummymandrels 222B′ (instead of all of dummy mandrels 222B), such that finregion 224 and fin region 226 each have one of dummy mandrels 222Bdisposed adjacent to mandrels 222A that are classified as iso mandrels.In the depicted embodiment, remaining dummy mandrels 222B are disposeddirectly adjacent to mandrels 222A, thereby defining a spacing S3between dummy mandrels 222B in fin active region 224 and fin activeregion 226 that is less than spacing S2. Remaining dummy mandrels 222Breduce left/right loading of innermost mandrels 222A (for example, fromS+S2 to S+S). In some implementations, left/right loading of innermostmandrels 222A is substantially equal to left/right loading of outermostmandrels 222A. For example, left/right loading of innermost mandrels222A and outermost mandrels 222A is S+S. The present disclosurecontemplates any subset of dummy mandrels removed, so long as remainingdummy mandrels reduce left/right loading of isolated mandrels, such asinnermost mandrels 222A, to less than or equal to a threshold left/rightloading. In some implementations, when spacing between mandrels of finactive regions, such as spacing S2, is greater than or equal to athreshold spacing (for example, defining a spacing that has beendetermined to result in unacceptable levels of fin etch iso/denseloading), the fin cut first process leaves at least one dummy mandrel ineach fin active region to define a spacing, such as spacing S3, betweendummy fins of the fin active regions. In such implementations, whenspacing between mandrels of fin active regions is less than thethreshold spacing, all dummy mandrels are removed between mandrelsdefining the fin active regions.

Removing subset of dummy mandrels 222B′ includes forming a patternedmasking layer over mandrel layer 220 that includes a cut patterndefining protected mandrels (here, mandrels 222A and at least one dummymandrel 222B disposed adjacent to each mandrel 222A classified as an isomandrel) and unprotected (unwanted) mandrels (here, subset of dummymandrels 222B′) and etching the unprotected mandrels using the patternedmasking layer as an etch mask. In some implementations, the cut patterndefines an opening in the patterned masking layer that exposes theunprotected mandrels. In some implementations, the patterned maskinglayer is a patterned resist layer formed by a lithography process, suchas those described herein. In some implementations, the patternedmasking layer is a patterned hard mask layer, which is formed bydepositing a hard mask layer over mandrel layer 220, forming a patternedresist layer having the cut pattern using a lithography process, such asthose described herein, and etching the hard mask layer using thepatterned resist layer as an etch mask, such that the patterned hardmask layer includes the cut pattern exposing the unprotected mandrels.In some implementations, the patterned masking layer has a multi-layerstructure. In some implementations, subset of dummy mandrels 222B′ isselectively etched without etching (or without significantly etching)the patterned masking layer. The etching process is a dry etchingprocess, a wet etching process, or combinations thereof. Various etchingparameters can be tuned to selectively etch subset of dummy mandrels222B′, such as etchant composition, etching temperature, etchingsolution concentration, etching time, etching pressure, source power, RFbias voltage, RF bias power, etchant flow rate, other suitable etchingparameters, or combinations thereof. In some implementations, a wetetching process uses an etching solution that includestetramethylammonium hydroxide (TMAH), hydrofluoric acid (HF), sulfuricacid (H₂SO₄), hydrogen chloride (HCl), ammonium hydroxide (NH₄OH),hydrogen peroxide (H₂O₂), other suitable wet etching constituent, orcombinations thereof. Thereafter, the patterned masking layer is removed(for example, by a resist stripping process and/or a selective etchingprocess), leaving mandrels 222A and dummy mandrels 222B as depicted inFIG. 2C.

Turning to FIG. 2D, a fin etching process is performed to define a finstructure 228A and a fin structure 228B (collectively referred to as afin layer) in a portion of substrate 205 using mandrel layer 220′ as anetch mask. Fin structure 228A is disposed in fin active region 224, andfin structure 228B is disposed in fin active region 226. In the depictedembodiment, fin structure 228A and fin structure 228B each include twoactive fins 230A and one dummy fin 232B, where dummy fins 232B areconfigured between active fins 230A of adjacent fin structures 228A,228B. Spacing of mandrel layer 220′ is transferred to the fin layer,such that fins of fin structures 228A, 228B are separated by spacing Sand dummy fins 230B of fin structures 228A, 228B are separated byspacing S3. Active fins 230A and dummy fins 230B are orientedsubstantially parallel to one another, each having a width defined in anx-direction, a length defined in a y-direction, and a height defined ina z-direction. Active fins 230A and dummy fins 230B have substantiallythe same widths, lengths, and heights. In the depicted embodiment, wheresubstrate 205 is a bulk substrate that includes silicon, active fins230A and dummy fins 230B include silicon. Alternatively, in someimplementations, where substrate 205 includes a semiconductor layerstack disposed over a bulk substrate, active fins 230A and dummy fins230B are defined in the semiconductor layer stack, such that active fins230A and dummy fins 230B include one or more semiconductor materiallayers. In furtherance of the depicted embodiment, trenches 232A aredefined between fins of fin structures 228A, 228B, and a trench 232B isdefined between adjacent fin structures 228A, 228B (here, between dummyfin 230B of fin structure 228A and dummy fin 230B of fin structure228B). Trenches 232A, 232B have sidewalls defined by sidewalls of activefins 230A, dummy fins 230B, and/or patterning layer 210 and bottomsdefined by top surfaces of substrate 205.

The fin etching process selectively etches patterning layer 210 andsubstrate 205 without etching (or without significantly etching) mandrellayer 220′, such that mandrels 222A and dummy mandrels 222B serve as anetch mask for removing portions of patterning layer 210 and substrate205. Inserting dummy fins 230B (which correspond with remaining dummymandrels 222B) adjacent to innermost, isolated active fins 230A (whichcorrespond with innermost mandrels 222A classified as iso mandrels)reduces fin etch iso/dense loading, such that widths of innermost activefins 230A are substantially similar to widths of outermost active fins220B. In some implementations, an area of substrate 205 correspondingwith innermost mandrels 222A etches at about the same rate as an area ofsubstrate 205 corresponding with outermost mandrels 222A. In someimplementations, fin etch iso/dense loading is reduced by as much as 45%compared to fin etch iso/dense loading that arises during conventionalfin cut first processes. The etching process is a dry etching process, awet etching process, or combinations thereof. In some implementations,the fin etching process is an anisotropic dry etching process (forexample, a RIE process) configured to substantially remove patterninglayer 210 and a portion of substrate 205 along the y-direction withoutremoval (or without significant removal) of patterning layer 210 and theportion of substrate 205 along the x-direction. In some implementations,a dry etching process uses a fluorine-containing precursor (for example,CF₄, SF₆, NF₃, CH₂F₂, CHF₃, and/or C₂F₆), an oxygen-containingprecursor, a chlorine-containing precursor (for example, Cl₂, CHCl₃,CCl₄, and/or BCl₃), a bromine-containing precursor (for example, HBrand/or CHBR₃), an iodine-containing precursor, other suitable precursor(which can be used to generate an etchant gas and/or etching plasma), orcombinations thereof. In some implementations, a wet etching processimplements an etching solution that includes TMAH, NH₄OH, H₂O₂, H₂SO₄,HF, HCl, other suitable wet etching constituent, or combinationsthereof. Various etching parameters can be tuned to selectively etchpatterning layer 210 and substrate 205, such as etchant composition,etching temperature, etching solution concentration, etching time,etching pressure, source power, RF bias voltage, RF bias power, etchantflow rate, other suitable etching parameters, or combinations thereof.The present disclosure contemplates any combination of etching processesand/or other processes for defining fin structure 228A and fin structure228B. Mandrel layer 220′ can be removed (for example, by an etchingprocess) after etching patterning layer 210 or substrate 205. Theetching process can selectively etch mandrels 222A and dummy mandrels222B without etching (or without significantly etching) patterning layer210 and/or substrate 205. In some implementations, patterning layer 210may be partially removed during the fin etching process. In someimplementations, patterning layer 210 is omitted. In suchimplementations, mandrel layer 220 includes a material that is differentthan substrate 205 to achieve etching selectivity during an etchingprocess, such that portions of substrate 205 can be selectively etchedwith minimal (or no) etching of mandrel layer 220′, and vice versa. Insuch implementations, mandrel layer 220′ can serves as an etch mask forpatterning substrate 205.

Turning to FIG. 2E, an isolation layer 240 is formed over FinFET device200. Isolation layer 240 covers a top surface of substrate 205,patterning layer 210, active fins 230A, and dummy fins 230B. Isolationlayer 240 also completely fills trenches 232A and partially fills trench232B, though the present disclosure contemplates embodiments whereisolation layer 240 partially fills trenches 232A and/or completelyfills trench 232B. Isolation layer 240 is subsequently patterned (whichis described in detail below) to form an isolation feature, such as ashallow trench isolation feature, that electrically isolates active fins230A from one another. Isolation layer 240 thus includes an isolationmaterial, such as silicon oxide, silicon nitride, silicon oxynitride,other suitable isolation material (for example, including silicon,oxygen, nitrogen, carbon, and/or other suitable isolation constituent),or combinations thereof. In the depicted embodiment, isolation layer 240includes an oxide material, such as silicon oxide, and can thus bereferred to as an oxide layer. In some implementations, isolation layer240 includes a multi-layer structure, such as a bulk dielectric layerdisposed over a liner dielectric layer, where the bulk dielectric layerand the liner dielectric layer include materials depending on designrequirements. In some implementations, isolation layer 240 includes adielectric layer disposed over a doped liner layer (including, forexample, boron silicate glass (BSG) or phosphosilicate glass (PSG)).Isolation layer 240 is deposited by CVD, physical vapor deposition(PVD), atomic layer deposition (ALD), high density plasma CVD (HDPCVD),metal organic CVD (MOCVD), remote plasma CVD (RPCVD), PECVD, LPCVD,atomic layer CVD (ALCVD), atmospheric pressure CVD (APCVD), othersuitable deposition process, or combinations thereof.

Turning to FIG. 2F, a fin end cut process is performed to remove aportion of active fins 230A and a portion of dummy fins 230B, therebydefining FinFET device regions of FinFET device 200. In the depictedembodiment, the fin end cut process forms a trench 245 that divides finactive region 224 into a FinFET device region 250A and a FinFET deviceregion 250B and fin active region 226 into a FinFET device region 250Cand a FinFET device region 250D. Trench 245 has sidewalls defined endsidewalls of isolation layer 240, active fins 230A, dummy fins 230B, andpatterning layer 210 and a bottom defined by the top surface ofsubstrate 205. Each of FinFET device regions 250A-250D includes twoactive fins 230A and one dummy fin 230B. Adjacent FinFET device regions250A-250D are separated by spacing S3 defined between dummy fins 230Balong the x-direction, instead of spacing S2 defined between active fins230A. For example, spacing S3 separates FinFET device region 250A andFinFET device region 250C, and spacing S3 separates FinFET device region250B and FinFET device region 250D. Trench 245 creates an end-to-endspacing 252 between adjacent FinFET device regions along they-direction. For example, ends of fins (often referred to as fin lineends) of FinFET device region 250A and ends of fins of FinFET deviceregion 250B are separated by end-to-end spacing 252 and ends of fins ofFinFET device region 250C and ends of fins of FinFET device region 250Dare separated by end-to-end spacing 252.

The fin end cut process includes depositing a masking layer overisolation layer 140 (in some implementations, the masking layer fillstrenches 232B); performing a lithography and etching process, such asthose described herein, to define a cut pattern in the masking layerthat exposes a portion of isolation layer 240; etching the exposedportion of isolation layer 240, thereby exposing a portion of activefins 230A and dummy fins 230B underlying isolation layer 240; etchingthe exposed portion of active fins 230A and dummy fins 230B; andremoving the masking layer, thereby forming trench 245. The maskinglayer can be removed before or after etching the exposed portion ofactive fins 230A and dummy fins 230B. In some implementations, themasking layer is a resist layer. In some implementations, the maskinglayer is a hard mask layer, which is formed by depositing a hard masklayer over isolation layer 240 (in some implementations, the hard masklayer fills trenches 232B), forming a patterned resist layer having thecut pattern using a lithography process, such as those described herein,and etching the hard mask layer using the patterned resist layer as anetch mask, such that the patterned hard mask layer includes the cutpattern. In some implementations, the masking layer has a multi-layerstructure. In some implementations, the exposed portion of isolationlayer 140 is selectively etched without etching (or withoutsignificantly etching) the masking layer and/or the portion of activefins 230A and dummy fins 230B underlying isolation layer 140. In someimplementations the exposed portion of active fins 230A and dummy fins230B is selectively etched without etching (or without significantlyetching) the masking layer and/or isolation layer 140. In someimplementations, an etching process is tuned throughout to etch siliconoxide without etching (or without significantly etching) silicon, andvice versa, to remove the exposed portions of isolation layer 140,active fins 230A, and dummy fins 230B. In some implementations, a dryetching process uses a fluorine-containing precursor (for example, CF₄,SF₆, NF₃, CH₂F₂, CHF₃, and/or C₂F₆), an oxygen-containing precursor, achlorine-containing precursor (for example, Cl₂, CHCl₃, CCl₄, and/orBCl₃), a bromine-containing precursor (for example, HBr and/or CHBR₃),an iodine-containing precursor, other suitable precursor (which can beused to generate an etchant gas and/or etching plasma), or combinationsthereof. In some implementations, a wet etching process implements anetching solution that includes TMAH, NH₄OH, H₂O₂, H₂SO₄, HF, HCl, othersuitable wet etching constituent, or combinations thereof. Variousetching parameters can be tuned to selectively etch isolation layer 140,active fins 230A, and/or dummy fins 230B, such as etchant composition,etching temperature, etching solution concentration, etching time,etching pressure, source power, RF bias voltage, RF bias power, etchantflow rate, other suitable etching parameters, or combinations thereof.The present disclosure contemplates any combination of etching processesand/or other processes for removing portions of active fins 230A anddummy fins 230B to define FinFET device regions 250A-250D, as depictedin FIG. 2F.

Turning to FIG. 2G, an isolation layer 260 is formed over FinFET device200. For example, isolation layer 260 covers isolation layer 240 andsurfaces of FinFET device 200 that define trench 245 (for example, theend sidewalls of isolation layer 240, active fins 230A, dummy fins 230B,and/or patterning layer 210 and the top surface of substrate 205). Infurtherance of the example, isolation layer 260 fills a remainingportion of trenches 232B (such that trenches 232B are completely filledby isolation layer 240 and isolation layer 260) and partially fillstrench 245, though the present disclosure contemplates embodiments whereisolation layer 260 partially fills trenches 232B and/or completelyfills trench 245. Isolation layer 260 is subsequently patterned (whichis described in detail below) to form an isolation feature, such as anSTI feature, that electrically isolates FinFET device regions 250A-250Dfrom one another. Isolation layer 260 thus includes an isolationmaterial, such as silicon oxide, silicon nitride, silicon oxynitride,other suitable isolation material (for example, including silicon,oxygen, nitrogen, carbon, and/or other suitable isolation constituent),or combinations thereof. In some implementations, the isolation materialis a high-k dielectric material (such that isolation layer 260 can bereferred to as a high-k dielectric layer), such as hafnium dioxide(HfO₂), HfSiO, HfSiON, HfTaO, HfTiO, HfZrO, zirconium oxide, aluminumoxide, hafnium dioxide-alumina (HfO₂—Al₂O₃) alloy, other suitable high-kdielectric material (for example, including hafnium, lanthanum,aluminum, and/or other suitable high-k dielectric material constituent),or combinations thereof. High-k dielectric material generally refers todielectric materials having a high dielectric constant, for example,greater than that of silicon oxide (k≈3.9). In the depicted embodiment,isolation layer 260 includes an isolation material that is differentthan the isolation material of isolation layer 240 to achieve etchingselectivity during an etching process, such that isolation layer 260 canbe etched without etching (or without significantly etching) isolationlayer 240, and vice versa. For example, isolation layer 260 includessilicon, oxygen, carbon, and nitrogen, such as silicon oxycarbonitride(for example, SiOCN). In another example, isolation layer 260 includes ahigh-k dielectric material. In some implementations, isolation layer 260includes a multi-layer structure, such as a bulk dielectric layerdisposed over a liner dielectric layer, where the bulk dielectric layerand the liner dielectric layer include materials depending on designrequirements. In some implementations, isolation layer 260 includes adielectric layer disposed over a doped liner layer (including, forexample, BSG or PSG). Isolation layer 260 is deposited by CVD, PVD, ALD,HDPCVD, MOCVD, RPCVD, PECVD, LPCVD, ALCVD, APCVD, other suitabledeposition process, or combinations thereof.

Turning to FIG. 2H, an isolation layer 265 is formed over FinFET device200. Isolation layer 265 fills a remaining portion of trench 245, suchthat trench 245 is completely filled by isolation layer 260 andisolation layer 265. Isolation layer 265 includes an isolation materialthat is different than the isolation material of isolation layer 260 toachieve etching selectivity during an etching process, such thatisolation layer 265 can be etched without etching (or withoutsignificantly etching) isolation layer 260, and vice versa. In thedepicted embodiment, isolation layer 265 is formed by a flowable CVD(FCVD) process, which includes depositing a flowable dielectric material(in some implementations, in a liquid state) over isolation layer 260and converting the flowable dielectric material into a solid dielectricmaterial (for example, by an annealing process). The flowable dielectricmaterial flows into trench 245 and conforms to exposed surfaces ofFinFET device 200, enabling void free filling of trench 245. Forexample, the FCVD process introduces a silicon-containing precursor andan oxidizer (collectively referred to as reactants) into a depositionchamber, where the silicon-containing precursor and the oxidizer reactand condense onto exposed surfaces of isolation layer 260 to form aflowable dielectric material. In some implementations, the flowabledielectric material is a flowable silicon-oxygen-and-nitrogen containingmaterial, where the flowable silicon-oxygen-and-nitrogen containingmaterial includes Si—OH, Si—H, Si—O, and/or Si—N bonds. An annealingprocess can convert the flowable silicon-oxygen-and-nitrogen materialinto a silicon-and-oxygen containing layer, such as a silicon oxidelayer. In such embodiments, the annealing process promotes formation ofSi—Si and/or Si—O bonds and reduces Si—N and/or Si—H bonds. In someimplementations, the annealing process converts Si—OH, Si—H, and/or Si—Nbonds into Si—O bonds. In some implementations, the annealing process isa thermal annealing process that heats FinFET device 200 to atemperature that can facilitate conversion of the flowable dielectricmaterial into the solid dielectric material. The thermal annealingprocess can heat FinFET device 200 via a substrate stage (on whichsubstrate 205 is secured), a lamp source, a laser source, other source,or combinations thereof. In some implementations, the flowabledielectric material is exposed to UV radiation during the annealingprocess. Alternatively or additionally, isolation layer 265 is formed bya high aspect ratio process (HARP) (implementing, for example, a TEOSprecursor and an O₃ precursor), HDPCVD (implementing, for example, anSiH₄ precursor and an O₂ precursor), other suitable process, orcombinations thereof. Thereafter, a planarization process, such as achemical mechanical polishing (CMP) process, is performed on the soliddielectric material until reaching and exposing isolation layer 260. Insome implementations, top surfaces of isolation layer 265 and isolationlayer 260 are substantially co-planar after the planarization process.In some implementations, an annealing process is subsequently performedto further cure and/or densify isolation layer 265.

Turning to FIG. 21, an etch back process is performed on isolation layer265. In the depicted embodiment, the etch back process reduces athickness T1 of isolation layer 265 to a thickness T2, thereby forming atrench 267 between FinFET device regions 250A, 250B and FinFET deviceregions 250C, 250D. Trench 267 has sidewalls and a bottom defined byisolation layer 260. The etch back process is a dry etching process, awet etching process, or combinations thereof configured to selectivelyetch isolation layer 265 without (or minimally) etching isolation layer260. In some implementations, an etching chemistry of the etch backprocess is tuned to selectively etch silicon oxide without etching (orwithout significantly etching) silicon oxycarbonitride or a high-kdielectric material.

FIGS. 2J-2L depict a dummy fin replacement process, where dummy fins230B are replaced with dielectric fins. Turning to FIG. 2J, dummy fins230B are removed from FinFET device regions 250A-250D, thereby formingfin openings 270, which are subsequently filled with a dielectricmaterial as described below. Removing dummy fins 230B includesdepositing a masking layer over isolation layer 260 and isolation layer265 (in some implementations, the masking layer fills trench 267);performing a lithography and etching process, such as those describedherein, to define openings in the masking layer that expose dummy fins230B (in the depicted embodiment, four opening are formed in the maskinglayer, where each opening exposes a portion of isolation layer 260overlying a respective dummy fin 230B); etching the exposed portion ofisolation layer 260, thereby exposing a portion of isolation layer 240underlying isolation layer 260 that overlies dummy fins 230B; etchingthe exposed portion of isolation layer 240, thereby exposing patterninglayer 210 disposed over dummy fins 230B; etching the exposed patterninglayer 210, thereby exposing dummy fins 230; etching the exposed dummyfins 230B, thereby forming fin trenches 270; and removing the maskinglayer. In the depicted embodiment, dummy fins 230B are not completelyremoved, leaving remainder dummy fins 230B′ that define bottoms of finopenings 270. In some implementations, dummy fins 230B are completelyremoved, such that the top surface of substrate 205 defines bottoms offin openings 270. The masking layer can be removed before or afteretching dummy fins 230B. In some implementations, the masking layer is aresist layer. In some implementations, the masking layer is a hard masklayer, which is formed by depositing a hard mask layer over isolationlayer 260 and isolation layer 265 (in some implementations, the hardmask layer fills trench 267), forming a patterned resist layer havingthe opening using a lithography and etching process, such as thosedescribed herein, and etching the hard mask layer using the patternedresist layer as an etch mask, such that the patterned hard mask layerincludes the opening. In some implementations, the masking layer has amulti-layer structure.

Various selective etching processes are performed to etch isolationlayer 260, isolation layer 240, patterning layer 210, and dummy fins230B to form fin openings 270. The exposed portion of isolation layer260 is selectively etched without etching (or without significantlyetching) the masking layer and/or isolation layer 240. For example, anetching chemistry of the etching process is tuned to selectively etchsilicon oxycarbonitride or high-k dielectric material without etching(or without significantly etching) silicon oxide and/or resist material.The exposed portion of isolation layer 240 is selectively etched withoutetching (or without significantly etching) the masking layer, isolationlayer 260, and/or patterning layer 210. For example, an etchingchemistry of the etching process is tuned to selectively etch siliconoxide without etching (or without significantly etching) etching siliconnitride, resist material, silicon oxycarbonitride, and/or high-kdielectric material. The exposed patterning layer 210 disposed overdummy fins 230B is selectively etched without etching (or withoutsignificantly etching) the masking layer, isolation layer 265, isolationlayer 240, and/or dummy fins 230B. For example, an etching chemistry ofthe etching process is tuned to selectively etch silicon nitride and/orsilicon oxide without etching (or without significantly etching) etchingsilicon and/or a resist material. The exposed dummy fins 230B areselectively etched without etching (or without significantly etching)the masking layer, isolation layer 265, and/or isolation layer 240. Forexample, an etching chemistry of the etching process is tuned toselectively etch silicon without etching (or without significantlyetching) silicon oxycarbonitride, high-k dielectric material, siliconoxide, and/or resist material. In the depicted embodiment, sincepatterning layer 210 includes some constituents in common with isolationlayer 265 and isolation layer 240, isolation layer 265 and/or isolationlayer 240 may be partially etched during etching of patterning layer210. For example, where pad layer 212 of patterning layer 210 includessilicon oxide, mask layer 214 of patterning layer 210 includes siliconnitride, isolation layer 265 includes silicon oxycarbonitride, andisolation layer 240 includes silicon oxide, etching of patterning layer210 partially etches isolation layer 265 and/or isolation layer 240underlying the masking layer, such that fin openings 270 have a firstportion having a first width (formed by etching isolation layer 265,isolation layer 240, and patterning layer 210) disposed over a secondportion having a second width (formed by etching dummy fins 230B), wherethe first width is greater than the second width. In someimplementations, etching mask layer 214 partially etches isolation layer240 disposed under the masking layer and etching pad layer 212 partiallyetches isolation layer 240 disposed under the masking layer, whichexpands a width of fin openings 270. In some implementations, theselective etching processes utilize a dry etching process thatimplements a fluorine-containing precursor (for example, CF₄, SF₆, NF₃,CH₂F₂, CHF₃, and/or C₂F₆), an oxygen-containing precursor, achlorine-containing precursor (for example, Cl₂, CHCl₃, CCl₄, and/orBCl₃), a bromine-containing precursor (for example, HBr and/or CHBR₃),an iodine-containing precursor, other suitable precursor (which can beused to generate an etchant gas and/or etching plasma), or combinationsthereof. In some implementations, the selective etching processesutilize a wet etching process implements an etching solution thatincludes TMAH, NH₄OH, H₂O₂, H₂SO₄, HF, HCl, other suitable wet etchingconstituent, or combinations thereof. Various etching parameters can betuned to selectively etch isolation layer 260, isolation layer 240,patterning layer 210, and/or dummy fins 230B, such as etchantcomposition, etching temperature, etching solution concentration,etching time, etching pressure, source power, RF bias voltage, RF biaspower, etchant flow rate, other suitable etching parameters, orcombinations thereof. The present disclosure contemplates anycombination of etching processes and/or other processes for removingdummy fins 230B.

Turning to FIG. 2K, fin openings 270 are filled with a dielectricmaterial. For example, a dielectric layer 280 is formed over FinFETdevice 200, and dielectric layer 285 is formed over dielectric layer280. In the depicted embodiment, dielectric layer 280 fills fin openings270 and trench 267, and dielectric layer 285 is disposed over a topsurface of dielectric layer 280. Dielectric layer 280 and dielectriclayer 285 include any suitable dielectric material, such as siliconoxide, silicon nitride, silicon oxynitride, other suitable dielectricmaterial (for example, including silicon, oxygen, nitrogen, carbon,and/or other suitable dielectric constituent), or combinations thereof.In some implementations, the dielectric material is a high-k dielectricmaterial (such that dielectric layer 280 and/or dielectric layer 285 canbe referred to as a high-k dielectric layer), such as HfO₂, HfSiO,HfSiON, HfTaO, HfTiO, HfZrO, zirconium oxide, aluminum oxide, HfO₂—Al₂O₃alloy, other suitable high-k dielectric material (for example, includinghafnium, lanthanum, aluminum, and/or other suitable high-k dielectricmaterial constituent), or combinations thereof. A material of dielectriclayer 280 is different than a material of dielectric layer 285. In thedepicted embodiment, a material of dielectric layer 280 is the same as amaterial of isolation layer 260, and a material of dielectric layer 285is the same as a material of isolation layer 240. For example,dielectric layer 280 includes silicon, oxygen, carbon, and/or nitrogen,such as silicon oxycarbonitride or silicon oxycarbide (SiOC), anddielectric layer 285 includes silicon and oxygen, such as silicon oxide.In another example, dielectric layer 280 includes a metal oxideconfigured as a high-k dielectric material, such as HfO₂, ZrO₂, orZrSiO₂, and dielectric layer 285 includes silicon oxide. The presentdisclosure further contemplates implementations where a material ofdielectric layer 280 is different than a material of isolation layer260, and a material of dielectric layer 285 is different than a materialof isolation layer 240. In some implementations, dielectric layer 280and/or dielectric layer 285 include a multi-layer structure. Dielectriclayer 280 and/or dielectric layer 285 is deposited by CVD, PVD, ALD,HDPCVD, MOCVD, RPCVD, PECVD, LPCVD, ALCVD, APCVD, other suitabledeposition process, or combinations thereof.

Turning to FIG. 2L, a planarization process, such as a CMP process, isperformed until reaching active fins 230A, such that active fins 230Afunction as a planarization (or CMP) stop layer. The planarizationprocess removes any dielectric material overlying (or above) topsurfaces of active fins 230A, such as dielectric layer 285, a portion ofdielectric layer 280, a portion of isolation layer 260, a portion ofisolation layer 240, and patterning layer 210 disposed over active fins230A, thereby forming dielectric fins 290, which replace dummy fins230B. A width, a length, and a height of dielectric fins 290 issubstantially the same as a width, a length, and a height of active fins230A. In some implementations, the width is about 6 nm to about 11 nm.In the depicted embodiment, dielectric fins 290 include dielectric layer280 disposed over remaining dummy fins 230B′, such that dielectric fins290 include a dielectric portion disposed over a semiconductor portion.In some implementations, a height of the dielectric portion ofdielectric fins 290 (here, dielectric layer 280) is about 100 nm toabout 200 nm. Alternatively, where dummy fins 230B are completelyremoved, dielectric fins 290 include dielectric layer 280, such thatdielectric fins 290 include only the dielectric portion.

The planarization process also results in isolation features 240′, adielectric feature 292A, a dielectric feature 292B, and an isolationfeature 294 of FinFET device 200. Isolation features 240′, which includeisolation layer 240, separate and isolate adjacent fins in each ofFinFET device regions 250A-250D. For example, each of FinFET deviceregions 250A-250D includes two active fins 230A and one of dielectricfins 290, which are separated by isolation features 240′. Dielectricfeatures 292A, 292B, both of which include isolation layer 260, separateadjacent FinFET device regions along a fin width direction (here, thex-direction). For example, dielectric features 292A separates FinFETdevice region 250A from FinFET device region 250C, and dielectricfeature 292B separates FinFET device region 250B from FinFET deviceregion 250D. Dielectric feature 292A is disposed between dielectric fins290 of FinFET device regions 250A, 250C, and dielectric feature 292B isdisposed between dielectric fins 290 of FinFET device regions 250B,250D. In some implementations, dielectric features 292A, 292B aredisposed in isolation features 240′, such that isolation features 240′are disposed along sidewalls and bottoms of dielectric features 292A,292B. Isolation feature 294 separates adjacent FinFET device regionsalong a fin length direction (here, the y-direction). For example,isolation feature 294 separates and isolates FinFET device region 250Afrom FinFET device region 250B and FinFET device region 250C from FinFETdevice region 250D. Isolation feature 294 is disposed between ends ofactive fins 230A of FinFET device regions 250A, 250B and ends of activefins 230A of FinFET device regions 250C, 250D. In the depictedembodiment, isolation feature 294 includes isolation layer 260,isolation layer 265, and isolation layer 280, where isolation layer 260is configured as a liner layer of isolation feature 294 and isolationlayer 265 and isolation layer 280 are configured as a bulk layer ofisolation feature 294. In some implementations, top surfaces of activefins 230A, isolation layer 240, dielectric fins 290, dielectric feature292A, dielectric feature 292B, and isolation feature 294 aresubstantially co-planar after the planarization process.

Turning to FIG. 2M, isolation features 240′ are recessed, such thatactive fins 230A, dielectric fins 290, dielectric feature 292A,dielectric feature 292B, and isolation feature 294 extend (protrude)from between neighboring isolation features 240′. For example, isolationfeatures 240′ surround a bottom portion of active fins 230A, therebydefining upper fin active regions of active fins 230A (generallyreferring to a portion of active fins 230A that extend from a topsurface of isolation features 240′) and lower fin active regions ofactive fins 230A (generally referring to a portion of active fins 230Asurrounded by isolation features 240′, which extend from a top surfaceof substrate 205 to the top surface of isolation features 240′). In someimplementations, an etch back process recesses isolation layer 240 untilachieving a desired (target) height of upper fin active regions ofactive fins 230A. Isolation features 240′ further surround a bottomportion of dielectric fins 290, dielectric feature 292A, dielectricfeature 292B, and isolation feature 294. The etch back process is a dryetching process, a wet etching process, or combinations thereof. Theetch back process selectively etches isolation layer 240 without etching(or without significantly etching) active fins 230A, dielectric fins290, dielectric feature 292A, dielectric feature 292B, and/or isolationfeature 294. For example, an etching chemistry is tuned to selectivelyetch silicon oxide without etching (or without significantly etching)silicon, silicon oxycarbonitride, and/or high-k dielectric material.

Turning to FIGS. 2N-2P, fabrication of FinFET device 200 can continue.For example, fabrication can continue with forming a dummy gate, formingepitaxial source/drain features, forming an interlevel dielectric (ILD)layer, replacing the dummy gate with a metal gate, and forming amultilayer interconnect structure. Turning to FIG. 2N, various gatestructures are formed over active fins 230A and dielectric fins 290,such as a gate structure 300A, a gate structure 300B, a gate structure300C, a gate structure 300D, and a gate structure 300E. Gate structures300A-300E extend along the x-direction (for example, substantiallyperpendicular to active fins 230A and dielectric fins 290) and traversefin structures of respective FinFET device regions 250A-250D, such thatgate structures 300A-300E wrap upper fin active regions of respectiveactive fins 230A and dielectric fins 290. Gate structure 300A isdisposed over channel regions of active fins 230A in FinFET deviceregions 250A, 250C, and gate structure 300E is disposed over respectivechannel regions of active fins 230A in FinFET device regions 250B, 250D.Gate structures 300A, 300E wrap the channel regions of respective activefins 230A, thereby interposing respective source/drain regions ofrespective active fins 230A. Gate structures 300A, 300E engage thechannel regions of respective fins 230A, such that current can flowbetween the source/drain regions of respective fins 230A duringoperation. Gate structure 300B wraps portions of active fins 230A inFinFET device regions 250A, 250C, positioned such that a source/drainregion of active fins 230A in FinFET device regions 250A, 250C isdisposed between gate structure 300B and gate structure 300A, and gatestructure 300D wraps portions of active fins 230A in FinFET deviceregions 250B, 250D, positioned such that a source/drain region of activefins 230A in FinFET device regions 250B, 250D is disposed between gatestructure 300D and gate structure 300E. Gate structures 300B, 300D arefurther partially disposed over isolation feature 294. Gate structure300C is disposed over isolation feature 294. In some implementations,gate structures 300A, 300E are active gate structures, whereas gatestructure 300B-300D are dummy gate structures. “Active gate structure”generally refers to an electrically functional gate structure of FinFETdevice 200, whereas “dummy gate structure” generally refers to anelectrically non-functional gate structure of FinFET device 200. In someimplementations, a dummy gate structure mimics physical properties of anactive gate structure, such as physical dimensions of the active gatestructure, yet is inoperable (in other words, does not enable current toflow). In some implementations, gate structures 300B-300D enable asubstantially uniform processing environment, for example, enablinguniform epitaxial material growth in source/drain regions of active fins230A (for example, when forming epitaxial source/drain features),uniform etch rates in source/drain regions of active fins 230A (forexample, when forming source/drain recesses), and/or uniform,substantially planar surfaces (for example, by reducing (or preventing)CMP-induced dishing effects).

Gate structures 300A-300E include gate stacks configured to achievedesired functionality according to design requirements of FinFET device200, such that gate structures 300A-300E include the same or differentlayers and/or materials. Gate structures 300A-300E are fabricatedaccording to a gate last process, such that gate structures 300A-300Ehave dummy gates 302 in FIG. 2N, which are subsequently replaced withmetal gates. Dummy gates 302 include, for example, an interfacial layer304 (including, for example, silicon oxide), a dummy gate electrode 306(including, for example, polysilicon), and a hard mask layer 308(including, for example, silicon nitride). In some implementations,dummy gates 302 include a dummy gate dielectric disposed between dummygate electrode 306 and interfacial layer 304. The dummy gate dielectricincludes a dielectric material, such as silicon oxide, a high-kdielectric material, other suitable dielectric material, or combinationsthereof. Dummy gates 302 can include numerous other layers, for example,capping layers, interface layers, diffusion layers, barrier layers, orcombinations thereof. Dummy gates 302 are formed by depositionprocesses, lithography processes, etching processes, other suitableprocesses, or combinations thereof. For example, a deposition process isperformed to form a dummy gate electrode layer over substrate 205,particularly over active fins 230A and dielectric fins 290. In someimplementations, a deposition process is performed to form a dummy gatedielectric layer over active fins 230A and dielectric fins 290 beforeforming the dummy gate electrode layer, where the dummy gate electrodelayer is formed over the dummy gate dielectric layer. The depositionprocess includes CVD, PVD, ALD, HDPCVD, MOCVD, RPCVD, PECVD, LPCVD,ALCVD, APCVD, plating, other suitable methods, or combinations thereof.A lithography patterning and etching process is then performed topattern the dummy gate electrode layer (and, in some implementations,the dummy gate dielectric layer) to form dummy gates 302, such thatdummy gates 302 wrap active fins 230A as depicted. The lithographypatterning processes include resist coating (for example, spin-oncoating), soft baking, mask aligning, exposure, post-exposure baking,developing the resist, rinsing, drying (for example, hard baking), othersuitable processes, or combinations thereof. Alternatively, thelithography exposing process is assisted, implemented, or replaced byother methods, such as maskless lithography, electron-beam writing, orion-beam writing. In yet another alternative, the lithography patterningprocess implements nanoimprint technology. The etching processes includedry etching processes, wet etching processes, other etching methods, orcombinations thereof.

Turning to FIG. 20, processing continues with forming gate spacers 310of gate structures 300A-300E. Gate spacers 310 are disposed adjacent to(for example, along sidewalls of) dummy gates 302. In someimplementations, gate spacers 310 fill spaces between upper portions ofactive fins 230A, dielectric fins 290, dielectric feature 292A, and/ordielectric feature 292B. Gate spacers 310 are formed by any suitableprocess and include a dielectric material. The dielectric material caninclude silicon, oxygen, carbon, nitrogen, other suitable material, orcombinations thereof (for example, silicon oxide, silicon nitride,silicon oxynitride, or silicon carbide). For example, in the depictedembodiment, a dielectric layer including silicon and nitrogen, such as asilicon nitride layer, can be deposited over substrate 205 andsubsequently anisotropically etched to form gate spacers 310. In someimplementations, gate spacers 310 include a multi-layer structure, suchas a first dielectric layer that includes silicon nitride and a seconddielectric layer that includes silicon oxide. In some implementations,gate spacers 310 include more than one set of spacers, such as sealspacers, offset spacers, sacrificial spacers, dummy spacers, and/or mainspacers, formed adjacent to the gate stacks. In such implementations,the various sets of spacers can include materials having different etchrates. For example, a first dielectric layer including silicon andoxygen can be deposited over FinFET device 200 and subsequentlyanisotropically etched to form a first spacer set adjacent to the gatestacks, and a second dielectric layer including silicon and nitrogen canbe deposited over FinFET device 200 and subsequently anisotropicallyetched to form a second spacer set adjacent to the first spacer set.Implantation, diffusion, and/or annealing processes may be performed toform lightly doped source and drain (LDD) features and/or heavily dopedsource and drain (HDD) features (both of which are not shown) insource/drain regions of active fins 230A before and/or after forminggate spacers 310.

Source features and drain features (referred to as source/drainfeatures) are formed in source/drain regions of active fins 230A. Forexample, semiconductor material is epitaxially grown on active fins230A, forming epitaxial source/drain features 315. In the depictedembodiment, a fin recess process (for example, an etch back process) isperformed on source/drain regions of active fins 230A, such thatepitaxial source/drain features 315 are grown from recessed active fins230A′. In some implementations, dielectric fins 290, dielectric feature292A, dielectric feature 292B, isolation feature 294, and/or gatespacers 310 disposed between upper portions of active fins 230A anddielectric fins 290 are partially etched during the fin recess processand/or other etching process, such that a height of dielectric fins 290,dielectric feature 292A, dielectric feature 292B, and/or isolationfeature 294 underlying gate structures 300A-300E is greater than aheight of dielectric fins 290, dielectric feature 292A, dielectricfeature 292B, and/or isolation feature 294 not underlying gatestructures 300A-300E. In such implementations, such as depicted in FIG.20, dielectric fins 290 have a first portion having a top surface thatis higher than a bottom surface of epitaxial source/drain features 315and lower than a top surface of epitaxial source/drain features 315 (forexample, the portion of dielectric fins 290 underlying gate structures300A-300E) and a second portion having a top surface that is lower thanthe bottom surface of epitaxial source/drain features 315 (for example,the portion of dielectric fins 290 not underlying gate structures300A-300E). In some implementations, source/drain regions of active fins230 are not subjected to a fin recess process, such that epitaxialsource/drain features 315 are grown from and wrap the upper fin activeregions of active fins 230A. In furtherance of the depicted embodiment,epitaxial source/drain features 315 extend (grow) laterally along thex-direction (in some implementations, substantially perpendicular torecessed fins 230A′), such that epitaxial source/drain features 315 aremerged epitaxial source/drain features that span more than one recessedactive fin 230A′. In some implementations, epitaxial source/drainfeatures 315 include partially merged portions (with interruption (orgaps) between epitaxial material grown from adjacent recessed activefins 230A′) and/or fully merged portions (without interruption (or gaps)between epitaxial material grown from adjacent recessed active fins230′).

An epitaxy process can implement CVD deposition techniques (for example,vapor-phase epitaxy (VPE), ultra-high vacuum CVD (UHV-CVD), LPCVD,and/or PECVD), molecular beam epitaxy, other suitable SEG processes, orcombinations thereof. The epitaxy process can use gaseous and/or liquidprecursors, which interact with the composition of recessed active fins230A′. Epitaxial source/drain features 315 are doped with n-type dopantsand/or p-type dopants. In the depicted embodiment, epitaxialsource/drain features 315 are configured depending on a type of FinFETfabricated in their respective FinFET device region. For example, inFinFET device regions 250A-250D that are configured for n-type FinFETs,epitaxial source/drain features 315 can include epitaxial layersincluding silicon and/or carbon, where silicon-containing epitaxiallayers or silicon-carbon-containing epitaxial layers are doped withphosphorous, arsenic, other n-type dopant, or combinations thereof (forexample, forming an Si:P epitaxial layer, an Si:C epitaxial layer, or anSi:C:P epitaxial layer). In furtherance of the example, in FinFET deviceregions 250A-250D that are configured for p-type FinFETs, epitaxialsource/drain features 315 can include epitaxial layers including siliconand/or germanium, where the silicon germanium containing epitaxiallayers are doped with boron, carbon, other p-type dopant, orcombinations thereof (for example, forming an Si:Ge:B epitaxial layer oran Si:Ge:C epitaxial layer). In some implementations, epitaxialsource/drain features 315 include materials and/or dopants that achievedesired tensile stress and/or compressive stress in the channel regions.In some implementations, epitaxial source/drain features 315 are dopedduring deposition by adding impurities to a source material of theepitaxy process. In some implementations, epitaxial source/drainfeatures 315 are doped by an ion implantation process subsequent to adeposition process. In some implementations, annealing processes areperformed to activate dopants in epitaxial source/drain features 315and/or other source/drain features of FinFET device 200, such as HDDregions and/or LDD regions.

Turning to FIG. 2P, an ILD layer 320 is formed over FinFET device 200,particularly over epitaxial source/drain features 315, gate structures300A-300E, dielectric fins 290, dielectric feature 292A, dielectricfeature 292B, and isolation feature 294. In some implementations, ILDlayer 320 is a portion of a multilayer interconnect (MLI) feature thatelectrically couples various devices (for example, transistors,resistors, capacitors, and/or inductors) and/or components (for example,gate structures and/or source/drain features) of FinFET device 200, suchthat the various devices and/or components can operate as specified bydesign requirements of FinFET device 200. ILD layer 320 includes adielectric material including, for example, silicon oxide, siliconnitride, silicon oxynitride, TEOS formed oxide, PSG, BPSG, low-kdielectric material, other suitable dielectric material, or combinationsthereof. Exemplary low-k dielectric materials include FSG, carbon dopedsilicon oxide, Black Diamond® (Applied Materials of Santa Clara,Calif.), Xerogel, Aerogel, amorphous fluorinated carbon, Parylene, BCB,SILK (Dow Chemical, Midland, Mich.), polyimide, other low-k dielectricmaterial, or combinations thereof. In some implementations, ILD layer320 has a multilayer structure having multiple dielectric materials. Insome implementations, a contact etch stop layer (CESL) is disposedbetween ILD layer 320 and epitaxial source/drain features 315, gatestructures 300A-300E, dielectric fins 290, dielectric feature 292A,dielectric feature 292B, and/or isolation feature 294. The CESL includesa material different than ILD layer 320, such as a dielectric materialthat is different than the dielectric material of ILD layer 320. In thedepicted embodiment, where ILD layer 320 includes a low-k dielectricmaterial, the CESL includes silicon and nitrogen (for example, siliconnitride or silicon oxynitride). ILD layer 320 and/or the CESL is formed,for example, by a deposition process (such as CVD, PVD, ALD, FCVD,HDPCVD, MOCVD, RPCVD, PECVD, LPCVD, ALCVD, APCVD, plating, othersuitable methods, or combinations thereof). Subsequent to the depositionof ILD layer 320 and/or the CESL, a CMP process and/or otherplanarization process is performed, such that a top portion of dummygates 310 of gate structure 300A-300E (here, hard mask layers 308) isreached (exposed).

Dummy gates 302 of gate structures 300A-300E are then replaced withmetal gates 330. In some implementations, dummy gates 302 are removed toform gate openings in gate structures 300A-300E (for example, havingsidewalls defined by gate spacers 310) that expose upper fin activeregions of a portion of active fins 230A and an upper portion ofdielectric fins 290. In some implementations, a portion of dummy gates302 is removed, such that gate openings expose an interfacial layerand/or a gate dielectric (and, in some implementations, a dummy gatedielectric) of dummy gates 302. The etching process is a dry etchingprocess, a wet etching process, or combinations thereof. In someimplementations, an etching process selectively removes dummy gates 302without etching (or without significantly) etching ILD layer 320, gatespacers 310, and/or other features of FinFET device 200. In someimplementations, a selective etching process can be tuned, such thatdummy gate electrodes 306 (including, for example, polysilicon) areetched without etching (or without significantly etching) an interfaciallayer and/or a dummy gate dielectric of dummy gates 302, gate spacers310, ILD layer 320, and/or other feature of FinFET device 200. Metalgates 310 are then formed in the gate openings. Metal gates 310 areconfigured to achieve desired functionality according to designrequirements of FinFET device 200, such that gate structures 300A-300Einclude the same or different layers and/or materials. In the depictedembodiment, metal gates 310 include gate dielectrics 332 and gateelectrodes 334. In implementations where gate structures 300A-300E spana p-type FinFET and an n-type FinFET (for example, where FinFET deviceregions 250A, 250B are configured with p-type FinFETs and FinFET deviceregions 250C, 250D are configured with n-type FinFETs, or vice versa),the present disclosure contemplates that gate structures 300A-300E caninclude different layers in regions corresponding with the p-type FinFETand the n-type FinFET. For example, a number, configuration, and/ormaterials of layers of gate dielectrics 332 and/or gate electrodes 334in FinFET device regions 250A, 250B may be different than a number,configuration, and/or materials of layers of gate dielectrics 332 and/orgate electrodes 334 in FinFET device regions 250C, 250D. In someimplementations, isolation features 338 are formed to separate metalgates 330 of FinFET device regions 250A, 250C and metal gates 330 ofFinFET device regions 250B, 250D. Isolation features 338 are formed byany suitable process, and in some implementations, include a dielectricmaterial.

Gate dielectrics 332 include a dielectric material, such as siliconoxide, high-k dielectric material, other suitable dielectric material,or combinations thereof. Gate dielectrics 332 wrap upper fin activeregions of a portion of active fins 230A and an upper region of aportion of dielectric fins 290. In the depicted embodiment, gatedielectrics 332 includes one or more high-k dielectric layers including,for example, hafnium, aluminum, zirconium, lanthanum, tantalum,titanium, yttrium, oxygen, nitrogen, other suitable constituent, orcombinations thereof. In some implementations, the one or more high-kdielectric layers include HfO₂, HfSiO, HfSiON, HfTaO, HMO, HfZrO, ZrO₂,Al₂O₃, HfO₂—Al₂O₃, TiO₂, Ta₂O₅, La₂O₃, Y₂O₃, other suitable high-kdielectric material, or combinations thereof. In some implementations,gate dielectrics 332 further include an interfacial layer (including adielectric material, such as silicon oxide) disposed between the high-kdielectric layer and respective active fins 230A and isolation features240′. In some implementations, gate dielectrics 332 are configured totune work functions of respective FinFETs in FinFET device regions250A-250D according to design requirements of FinFET device 200. Gatedielectrics 332 are formed by various processes, such as ALD, CVD, PVD,and/or other suitable process.

Gate electrodes 334 are respectively disposed over gate dielectrics 332.Gate electrodes 334 include an electrically conductive material. In someimplementations, gate electrodes 334 includes multiple layers, such asone or more capping layers, work function layers, glue/barrier layers,and/or metal fill (or bulk) layers. A capping layer can include amaterial that prevents or eliminates diffusion and/or reaction ofconstituents between gate dielectrics 332 and other layers of gatestructures 300A-300E (in particular, gate layers including metal). Insome implementation, the capping layer includes a metal and nitrogen,such as titanium nitride (TiN), tantalum nitride (TaN), tungsten nitride(W₂N), titanium silicon nitride (TiSiN), tantalum silicon nitride(TaSiN), or combinations thereof. A work function layer can include aconductive material tuned to have a desired work function (such as ann-type work function or a p-type work function), such as n-type workfunction materials and/or p-type work function materials. P-type workfunction materials include TiN, TaN, Ru, Mo, Al, WN, ZrSi₂, MoSi₂,TaSi₂, NiSi₂, WN, other p-type work function material, or combinationsthereof. N-type work function materials include Ti, Al, Ag, Mn, Zr,TiAl, TiAlC, TaC, TaCN, TaSiN, TaAl, TaAlC, TiAlN, other n-type workfunction material, or combinations thereof. A glue/barrier layer caninclude a material that promotes adhesion between adjacent layers, suchas the work function layer and the metal fill layer, and/or a materialthat blocks and/or reduces diffusion between gate layers, such as suchas the work function layer and the metal fill layer. For example, theglue/barrier layer includes metal (for example, W, Al, Ta, Ti, Ni, Cu,Co, other suitable metal, or combinations thereof), metal oxides, metalnitrides (for example, TiN), or combinations thereof. A metal fill layercan include a suitable conductive material, such as Al, W, and/or Cu. Insome implementations, a hard mask layer (including, for example, siliconnitride or silicon carbide) is disposed over gate electrodes 334. Gateelectrodes 334 are formed by various deposition processes, such as ALD,CVD, PVD, and/or other suitable process.

Various contacts can be formed to facilitate operation of FinFET device200. For example, fabrication of the MLI feature can continue. The MLIfeature includes a combination of dielectric layers (including ILD layer320) and electrically conductive layers (for example, metal layers)configured to form various interconnect structures. The conductivelayers are configured to form vertical interconnect features, such asdevice-level contacts and/or vias, and/or horizontal interconnectfeatures, such as conductive lines. Vertical interconnect featurestypically connect horizontal interconnect features in different layers(or different planes) of the MLI feature. During operation of FinFETdevice 200, the interconnect features are configured to route signalsbetween the devices and/or the components of FinFET device 200 and/ordistribute signals (for example, clock signals, voltage signals, and/orground signals) to the devices and/or the components of FinFET device200. The present disclosure contemplates the MLI feature including anynumber and/or configuration of dielectric layers and/or conductivelayers depending on design requirements of FinFET device 200.

In the depicted embodiment, device-level contacts 340, vias (not shown),and conductive lines (not shown) are formed in ILD layer 320 and/orother ILD layers of the MLI feature to form interconnect structures.Device-level contacts 340 (also referred to as local interconnects orlocal contacts) electrically couple and/or physically couple IC devicefeatures, such as features of FinFETs in FinFET device regions250A-250D. For example, device-level contacts 340 are metal-to-device(MD) contacts, which generally refer to contacts to a conductive region,such as source/drain regions, of FinFET device 200. In the depictedembodiment, device-level contacts 340 are disposed on respectiveepitaxial source/drain features 315, such that device-level contacts 340physically (or directly) connect the source/drain regions of FinFETs inFinFET device regions 250A-250D to the MLI feature (for example, torespective vias). Device-level contacts 340, vias, and conductive linesinclude any suitable electrically conductive material, such as Ta, Ti,Al, Cu, Co, W, TiN, TaN, other suitable conductive materials, orcombinations thereof. Various conductive materials can be combined toprovide device-level contacts 340, vias, and/or conductive lines withvarious layers, such as one or more barrier layers, adhesion layers,liner layers, bulk layers, other suitable layers, or combinationsthereof. In some implementations, device-level-contacts 340 include Ti,TiN, and/or Co; vias include Ti, TiN, and/or W; and conductive linesinclude Cu, Co, and/or Ru. Device-level contacts 340, vias, andconductive lines are formed by patterning ILD layer 320 and/or other ILDlayers of the MLI feature. Patterning the ILD layers can includelithography processes and/or etching processes to form openings(trenches), such as contact openings, via openings, and/or line openingsin respective ILD layers. In some implementations, the lithographyprocesses include forming a resist layer over respective ILD layers,exposing the resist layer to patterned radiation, and developing theexposed resist layer, thereby forming a patterned resist layer that canbe used as a masking element for etching opening(s) in respective ILDlayers. The etching processes include dry etching processes, wet etchingprocesses, other etching processes, or combinations thereof. Thereafter,the opening(s) are filled with one or more conductive materials. Theconductive material(s) can be deposited by PVD, CVD, ALD,electroplating, electroless plating, other suitable deposition process,or combinations thereof. Thereafter, any excess conductive material(s)can be removed by a planarization process, such as a CMP process,thereby planarizing a top surface of the ILD layers (for example, ILDlayer 320), device-level contacts 340, vias, and/or conductive lines.The present disclosure contemplates any configuration of device-levelcontacts, vias, and/or conductive lines.

Fin-like field effect transistor (FinFET) patterning methods aredisclosed herein for achieving fin width uniformity. Though method 100is applied herein to form fins of FinFET devices of FinFET device 200,method 100 can be applied in numerous ways to form other IC features ofIC devices. As one of many examples, the patterning techniques disclosedherein can be implemented to form gate features and/or other IC featureswith reduced etching loading effects. The present disclosure providesfor many different embodiments.

An exemplary method includes forming a mandrel layer over a substrateand performing a first cut to remove a portion of the mandrel layer,thereby leaving a mandrel feature and a dummy mandrel feature disposedover the substrate. The dummy mandrel feature is disposed directlyadjacent to the mandrel feature. The substrate is etched using themandrel feature and the dummy mandrel feature as an etch mask, therebyforming a dummy fin feature and an active fin feature. The dummy finfeature is separated from the active fin feature by a first spacingalong a first direction. A second cut is then performed to remove aportion of the dummy fin feature and a portion of the active finfeature, thereby forming dummy fins separated by a second spacing andactive fins separated by the second spacing. The second spacing is alonga second direction that is substantially perpendicular to the firstdirection. A third cut is then performed to remove the dummy fins,thereby forming fin openings. The fin openings are filled with adielectric material, such as a high-k dielectric material or a materialthat includes silicon, oxygen, and carbon, thereby forming dielectricfins. In some implementations, the method further includes forming afirst isolation layer over the dummy fin feature and the active finfeature before performing the second cut and forming a second isolationlayer over the first isolation layer after performing the second cut.The first isolation layer fills a trench defined between the dummy finfeature and the active fin feature. A material of the second isolationlayer is different than a material of the first isolation layer.

In some implementations, the mandrel feature is a first mandrel feature,the dummy mandrel feature is a first dummy mandrel feature, the dummyfin feature is a first dummy fin feature, the active fin feature is afirst active fin feature, the dummy fins are first dummy fins, theactive fins are first active fins, the fin openings are first finopenings, and the dielectric fins are first dielectric fins. In suchimplementations, performing the first cut can further include leaving asecond mandrel feature and a second dummy mandrel feature disposed overthe substrate. The second dummy mandrel feature is disposed directlyadjacent to the second mandrel feature. In such implementations, etchingthe substrate can further include using the second mandrel feature andthe second dummy mandrel feature as an etch mask, thereby forming asecond dummy fin feature and a second active fin feature separated bythe first spacing. In such implementations, performing the second cutcan further include removing a portion of the second dummy fin featureand a portion of the second active fin feature, thereby forming seconddummy fins separated by the second spacing and second active finsseparated by the second spacing. In such implementations, performing thethird cut can further include removing the second dummy fins, therebyforming second fin openings. In such implementations, filling the finopenings can further include forming second dielectric fins, wherein thefirst dielectric fins are separated from the second dielectric fins by athird spacing along the first direction, wherein the third spacing isgreater than the first spacing.

In some implementations, the trench defined between the dummy finfeature and the active fin feature is a first trench defined between thefirst dummy fin feature and the first active fin feature. In suchimplementations, forming the first isolation layer can further includeforming the first isolation layer over the second dummy fin feature andthe second active fin feature, wherein the first isolation layer fills asecond trench defined between the second dummy fin feature and thesecond active fin feature and partially fills a third trench definedbetween the second dummy fin feature and the first dummy fin feature. Insuch implementations, forming the second isolation layer over the firstisolation layer can further include filling a remaining portion of thethird trench and partially filling a fourth trench defined between endsof the first active fins, ends of the first dummy fins, ends of thesecond active fins, and ends of the second dummy fins. In someimplementations, the method further includes forming a third isolationlayer over the second isolation layer, wherein the third isolation layerpartially fills the fourth trench and a material of the third isolationlayer is different than a material of the first isolation layer and thesecond isolation layer.

In some implementations, performing the third cut includes performing aselective etch process to remove a portion of the second isolation layerand the first isolation layer to expose the first dummy fins and thesecond dummy fins and performing a selective etch process to remove theexposed first dummy fins and the exposed second dummy fins. In someimplementations, filling the fin openings includes depositing adielectric layer over the first isolation layer, the second isolationlayer, and the third isolation layer and performing a planarizationprocess to remove a portion of the dielectric layer, a portion of thesecond isolation layer, and a portion of the first isolation layer,thereby exposing the first active fins and the second active fins. Thedielectric layer fills the first fin openings, the second fin openings,and a remaining portion of the fourth trench, and further wherein amaterial of the dielectric layer is the same as a material of the secondisolation layer.

Another exemplary method includes forming a mandrel layer over asubstrate and performing a fin cut process to pattern the mandrel layerto define a first fin active region and a second fin active region. Themandrel layer includes an array of mandrels separated by a firstspacing, and the fin cut process removes a portion of the mandrel layer,such that a first mandrel and a first dummy mandrel of the array ofmandrels remain over the substrate defining the first fin active regionand a second mandrel and a second dummy mandrel of the array of mandrelsremain over the substrate defining the second fin active region. Thefirst dummy mandrel and the second dummy mandrel are separated by asecond spacing that is greater than the first spacing. The first dummymandrel and the second dummy mandrel are disposed between the firstmandrel and the second mandrel. The method further includes etching thesubstrate using the patterned mandrel layer as an etch mask to form afirst active fin feature and a first dummy fin feature in the first finactive region and a second active fin feature and a second dummy finfeature in the second fin active region. The method further includesperforming a fin end cut process to pattern the first active finfeature, the first dummy fin feature, the second active fin feature, andthe second dummy fin feature, thereby dividing the first active finfeature into first fins separated by an end-to-end spacing, the firstdummy fin feature into first dummy fins separated by the end-to-endspacing, the second active fin feature into second fins separated by theend-to-end spacing, and the second dummy fin feature into second dummyfins separated by the end-to-end spacing. The method further includesreplacing the first dummy fins and the second dummy fins with dielectricfins.

In some implementations, the method further includes forming a firstisolation layer over the first active fin feature, the second active finfeature, the first dummy fin feature, and the second dummy fin featurebefore performing the fin end cut process. The first isolation layerfills first trenches defined between the first fin feature and the firstdummy fin feature and between the second active fin feature and thesecond dummy fin feature. The first isolation layer also partially fillsa second trench defined between the first dummy fin feature and thesecond dummy fin feature. In some implementations, the first isolationlayer is etched back to form isolation features that isolate the firstfins and the second fins from the dielectric fins. In someimplementations, the method further includes forming a second isolationlayer over the first isolation layer after performing the fin end cutprocess. The second isolation layer fills a remaining portion of thesecond trench and partially fills a third trench defined between ends ofthe first fins, ends of the first dummy fins, ends of the second fins,and ends of the second fins. In some implementations, the method furtherincludes forming a third isolation layer over the second isolationlayer. The third isolation layer partially fills the third trench. Insome implementations, the third isolation layer is formed by performinga flowable chemical vapor deposition (FCVD) process to deposit anisolation material that fills the third trench and etching back theisolation material. In some implementations, the first dummy fins andthe second dummy fins are replaced with dielectric fins by etching aportion of the second isolation layer and the first isolation layer,Exposed first dummy fins and the second dummy fins are then etched toform fin openings, which are filled with a dielectric material. In someimplementations, filling the fin openings with the dielectric layerincludes depositing a dielectric layer over the first isolation layer,the second isolation layer, and the third isolation layer and performinga planarization process until reaching the first fins and the secondfins. The dielectric layer fills the fin openings and a remainingportion of the third trench.

An exemplary integrated circuit device includes a fin-like field effecttransistor (FinFET) device having a fin structure that includes adielectric fin and an active fin extending along a first direction. Thedielectric fin is disposed directly adjacent to the active fin. A widthof the dielectric fin is substantially the same as a width of the activefin. An isolation feature is disposed between the dielectric fin and theactive fin. A dielectric material of the dielectric fin is differentthan a dielectric material of the isolation feature. A gate structure isdisposed over a portion of the dielectric fin and the active fin,wherein the gate structure extends along a second direction that issubstantially perpendicular to the first direction.

In some implementations, the FinFET device is a first FinFET device, thefin structure is a first fin structure, the dielectric fin is a firstdielectric fin, the active fin is a first active fin, and the isolationfeature is a first isolation feature. In such implementations, theintegrated circuit device further includes a second FinFET device havinga second fin structure that includes a second dielectric fin and asecond active fin extending along the first direction. The seconddielectric fin is disposed directly adjacent to the second active fin. Awidth of the second dielectric fin is substantially the same as a widthof the second active fin. A second isolation feature is disposed betweenthe second dielectric fin and the second active fin. A dielectricmaterial of the second dielectric fin is different than a dielectricmaterial of the second isolation feature. In furtherance of suchimplementations, the gate structure is further disposed over a portionof the second dielectric fin and the second active fin, the first activefin and the first dielectric fin are separated by a first spacing, thesecond active fin and the second dielectric fin are separated by thefirst spacing, and the first dielectric fin and the second dielectricfin are disposed between the first active fin and the second active fin.The first dielectric fin and the second dielectric fin are separated bya second spacing that is greater than the first spacing. In someimplementations, the integrated circuit device further includes adielectric feature disposed between the first dielectric fin and thesecond dielectric fin. A width of the dielectric feature is greater thanthe width of the first dielectric fin and the width of the seconddielectric fin. In some implementations, the dielectric feature isseparated from the first dielectric fin and the second dielectric fin bythe first spacing.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method comprising: forming a mandrel layer overa substrate; performing a first cut to remove a portion of the mandrellayer, thereby leaving a mandrel feature and a dummy mandrel featuredisposed over the substrate, wherein the dummy mandrel feature isdisposed directly adjacent to the mandrel feature; etching the substrateusing the mandrel feature and the dummy mandrel feature as an etch mask,thereby forming a dummy fin feature and an active fin feature, whereinthe dummy fin feature is separated from the active fin feature by afirst spacing along a first direction; performing a second cut to removea portion of the dummy fin feature and a portion of the active finfeature, thereby forming dummy fins separated by a second spacing andactive fins separated by the second spacing, wherein the second spacingis along a second direction that is substantially perpendicular to thefirst direction; performing a third cut to remove the dummy fins,thereby forming fin openings; and filling the fin openings with adielectric material, thereby forming dielectric fins.
 2. The method ofclaim 1, wherein the filling the fin openings with the dielectricmaterial includes depositing a high-k dielectric material.
 3. The methodof claim 1, wherein the filling the fin openings with the dielectricmaterial includes depositing a material that includes silicon, oxygen,and carbon.
 4. The method of claim 1, further comprising: forming afirst isolation layer over the dummy fin feature and the active finfeature before performing the second cut, wherein the first isolationlayer fills a trench defined between the dummy fin feature and theactive fin feature; and forming a second isolation layer over the firstisolation layer after performing the second cut, wherein a material ofthe second isolation layer is different than a material of the firstisolation layer.
 5. The method of claim 4, wherein: the mandrel featureis a first mandrel feature, the dummy mandrel feature is a first dummymandrel feature, the dummy fin feature is a first dummy fin feature, theactive fin feature is a first active fin feature, the dummy fins arefirst dummy fins, the active fins are first active fins, the finopenings are first fin openings, and the dielectric fins are firstdielectric fins; the performing the first cut further includes leaving asecond mandrel feature and a second dummy mandrel feature disposed overthe substrate, wherein the second dummy mandrel feature is disposeddirectly adjacent to the second mandrel feature; the etching thesubstrate further includes using the second mandrel feature and thesecond dummy mandrel feature as an etch mask, thereby forming a seconddummy fin feature and a second active fin feature separated by the firstspacing; the performing the second cut further includes removing aportion of the second dummy fin feature and a portion of the secondactive fin feature, thereby forming second dummy fins separated by thesecond spacing and second active fins separated by the second spacing;the performing the third cut further includes removing the second dummyfins, thereby forming second fin openings; and the filling the finopenings further includes forming second dielectric fins, wherein thefirst dielectric fins are separated from the second dielectric fins by athird spacing along the first direction, wherein the third spacing isgreater than the first spacing.
 6. The method of claim 5, wherein: thetrench defined between the dummy fin feature and the active fin featureis a first trench defined between the first dummy fin feature and thefirst active fin feature; the forming the first isolation layer furtherincludes forming the first isolation layer over the second dummy finfeature and the second active fin feature, wherein the first isolationlayer fills a second trench defined between the second dummy fin featureand the second active fin feature and partially fills a third trenchdefined between the second dummy fin feature and the first dummy finfeature; and the forming the second isolation layer over the firstisolation layer further includes filling a remaining portion of thethird trench and partially filling a fourth trench defined between endsof the first active fins, ends of the first dummy fins, ends of thesecond active fins, and ends of the second dummy fins.
 7. The method ofclaim 6, further comprising forming a third isolation layer over thesecond isolation layer, wherein the third isolation layer partiallyfills the fourth trench and a material of the third isolation layer isdifferent than a material of the first isolation layer and the secondisolation layer.
 8. The method of claim 7, wherein: the performing thethird cut includes: performing a selective etch process to remove aportion of the second isolation layer and the first isolation layer toexpose the first dummy fins and the second dummy fins, and performing aselective etch process to remove the exposed first dummy fins and theexposed second dummy fins; and the filling the fin openings includes:depositing a dielectric layer over the first isolation layer, the secondisolation layer, and the third isolation layer, wherein the dielectriclayer fills the first fin openings, the second fin openings, and aremaining portion of the fourth trench, and further wherein a materialof the dielectric layer is the same as a material of the secondisolation layer, and performing a planarization process to remove aportion of the dielectric layer, a portion of the second isolationlayer, and a portion of the first isolation layer, thereby exposing thefirst active fins and the second active fins.
 9. A method comprising:forming a mandrel layer over a substrate, wherein the mandrel layerincludes an array of mandrels separated by a first spacing; performing afin cut process to pattern the mandrel layer to define a first finactive region and a second fin active region, wherein the fin cutprocess removes a portion of the mandrel layer, such that a firstmandrel and a first dummy mandrel of the array of mandrels remain overthe substrate defining the first fin active region and a second mandreland a second dummy mandrel of the array of mandrels remain over thesubstrate defining the second fin active region, wherein the first dummymandrel and the second dummy mandrel are separated by a second spacingthat is greater than the first spacing, wherein the first dummy mandreland the second dummy mandrel are disposed between the first mandrel andthe second mandrel; etching the substrate using the patterned mandrellayer as an etch mask to form a first active fin feature and a firstdummy fin feature in the first fin active region and a second active finfeature and a second dummy fin feature in the second fin active region;performing a fin end cut process to pattern the first active finfeature, the first dummy fin feature, the second active fin feature, andthe second dummy fin feature, thereby dividing the first active finfeature into first fins separated by an end-to-end spacing, the firstdummy fin feature into first dummy fins separated by the end-to-endspacing, the second active fin feature into second fins separated by theend-to-end spacing, and the second dummy fin feature into second dummyfins separated by the end-to-end spacing; and replacing the first dummyfins and the second dummy fins with dielectric fins.
 10. The method ofclaim 9, further comprising forming a first isolation layer over thefirst active fin feature, the second active fin feature, the first dummyfin feature, and the second dummy fin feature before performing the finend cut process, wherein the first isolation layer fills first trenchesdefined between the first fin feature and the first dummy fin featureand between the second active fin feature and the second dummy finfeature and partially fills a second trench defined between the firstdummy fin feature and the second dummy fin feature.
 11. The method ofclaim 10, further comprising forming a second isolation layer over thefirst isolation layer after performing the fin end cut process, whereinthe second isolation layer fills a remaining portion of the secondtrench and partially fills a third trench defined between ends of thefirst fins, ends of the first dummy fins, ends of the second fins, andends of the second fins.
 12. The method of claim 11, further comprisingforming a third isolation layer over the second isolation layer, whereinthe third isolation layer partially fills the third trench.
 13. Themethod of claim 12, wherein the forming the third isolation layerincludes: performing a flowable chemical vapor deposition (FCVD) processto deposit an isolation material that fills the third trench; andetching back the isolation material.
 14. The method of claim 12, whereinthe replacing the first dummy fins and the second dummy fins withdielectric fins includes: etching a portion of the second isolationlayer and the first isolation layer, thereby exposing the first dummyfins and the second dummy fins; etching the exposed first dummy fins andthe second dummy fins, thereby forming fin openings; and filling the finopenings with a dielectric layer.
 15. The method of claim 14, whereinthe filling the fin openings includes: depositing a dielectric layerover the first isolation layer, the second isolation layer, and thethird isolation layer, wherein the dielectric layer fills the finopenings and a remaining portion of the third trench; and performing aplanarization process until reaching the first fins and the second fins.16. The method of claim 14, further comprising etching back the firstisolation layer to form isolation features that isolate the first finsand the second fins from the dielectric fins.
 17. An integrated circuitdevice comprising: a fin-like field effect transistor (FinFET) devicehaving: a fin structure that includes a dielectric fin and an active finextending along a first direction, wherein the dielectric fin isdisposed directly adjacent to the active fin, and further wherein awidth of the dielectric fin is substantially the same as a width of theactive fin; an isolation feature disposed between the dielectric fin andthe active fin, wherein a dielectric material of the dielectric fin isdifferent than a dielectric material of the isolation feature; and agate structure disposed over a portion of the dielectric fin and theactive fin, wherein the gate structure extends along a second directionthat is substantially perpendicular to the first direction.
 18. Theintegrated circuit device of claim 17, wherein the FinFET device is afirst FinFET device, the fin structure is a first fin structure, thedielectric fin is a first dielectric fin, the active fin is a firstactive fin, the isolation feature is a first isolation feature, and theintegrated circuit device further includes a second FinFET devicehaving: a second fin structure that includes a second dielectric fin anda second active fin extending along the first direction, wherein thesecond dielectric fin is disposed directly adjacent to the second activefin, and further wherein a width of the second dielectric fin issubstantially the same as a width of the second active fin; and a secondisolation feature disposed between the second dielectric fin and thesecond active fin, wherein a dielectric material of the seconddielectric fin is different than a dielectric material of the secondisolation feature, wherein: the gate structure is further disposed overa portion of the second dielectric fin and the second active fin, thefirst active fin and the first dielectric fin are separated by a firstspacing, the second active fin and the second dielectric fin areseparated by the first spacing, and the first dielectric fin and thesecond dielectric fin are disposed between the first active fin and thesecond active fin, such that the first dielectric fin and the seconddielectric fin are separated by a second spacing that is greater thanthe first spacing.
 19. The integrated circuit device of claim 18,further comprising a dielectric feature disposed between the firstdielectric fin and the second dielectric fin, wherein a width of thedielectric feature is greater than the width of the first dielectric finand the width of the second dielectric fin.
 20. The integrated circuitdevice of claim 18, wherein the first dielectric fin and the seconddielectric fin each include a dielectric layer disposed over a dummyfin, wherein a height of the dummy fin is less than a height of thefirst active fin and the second active fin.